Introduction
It is essential to distinguish a true allergy from a pharmacological intolerance, as management and alternative treatments differ.
Symptoms
- Acute urticaria
- Angio-oedema (lips, eyelids, face)
- Widespread itching
- Worsening of asthma or difficulty breathing
- Delayed skin rash
- Rarely: anaphylactic reaction
Causes
- True allergic reactions (immunological mechanism)
- Non-allergic intolerance (inhibition of cyclo-oxygenase)
- Aspirin
- Ibuprofen
- Ketoprofen
- Diclofenac
- Naproxen
- Other NSAIDs
Diagnosis
- Detailed history (drug, timing, symptoms)
- Checking for a history of asthma or nasal polyps
- Clinical examination
- Targeted allergy tests: Skin tests (selected cases) Controlled challenge tests in a specialist setting
- Skin tests (selected cases)
- Controlled challenge tests in a specialist setting
Treatments
- Permanent avoidance of the NSAIDs responsible
- Antihistamines for skin symptoms
- Corticosteroids depending on severity
- Prescription of safe alternatives (paracetamol, selective drugs)
- Adrenaline auto-injector if there is a history of severe reaction
Management
Distinguish allergy from intolerance
Identify which NSAIDs to avoid
Suggest safe alternatives
Prevent serious reactions in the future